Adaptor apparatus for removal of a plug assembly from a well bore

ABSTRACT

An adaptor apparatus for use in facilitating removal and retrieval of a plug assembly from a well bore. The apparatus is structured for slidably entering, locking and sealing the plug assembly within the well bore. On further movement of the adaptor apparatus the plug assembly may be unsealed and an end of the apparatus connected to a pulling tool, whereby the plug assembly and adaptor apparatus are unitarily equalized and withdrawn from the well bore by a single wireline run.

BACKGROUND OF THE INVENTION

The invention relates to an adaptor apparatus for use in facilitating removal and retrieval of a plug assembly from a well bore. This is achieved by a single wireline run.

Conventional practices for removal and retrieval of plug assemblies from a well bore are cumbersome, inefficient and time consuming. Specifically, sand and debris tend to collect inside the plug assembly which causes difficulty for retrieval and creates increased rig time for fishing and bailing activity. Other operations to avoid bailing require extending the length of the prong fish neck of the plug assembly. This, however, requires two wireline runs to retrieve the plug assembly. An additional practice is to position debris barriers or a catcher tube above the plug assembly to catch the sand and debris. Again, this requires a minimum of two wireline deployments.

In accordance with the present invention, the adaptor apparatus thereof is designed to overcome all of these disadvantages and permit removal and retrieval of the plug assembly in one wireline run.

Another advantage of the invention is that it enables the plug assembly to be equalized and retrieved by a single wireline run.

SUMMARY OF THE INVENTION

The invention relates to an adaptor apparatus for use in facilitating removal and retrieval of a plug assembly from a well bore. The adaptor apparatus has means for slidably entering and locking the plug assembly within the well bore in internal, abutting engagement within the plug assembly at a first location. Additional means for unsealing the plug assembly when the adaptor apparatus is further slidably moved within the plug assembly to a second location is provided. Further means are provided for connecting an end of the adaptor apparatus to pulling means for pulling the adaptor apparatus from the well bore. Means are provided responsive to this pulling of the adaptor apparatus for unsealing the plug assembly and further means are provided responsive to this pulling of the adaptor apparatus for latching the plug assembly to the adaptor apparatus. In this manner, the plug assembly and the adaptor apparatus may be unitarily equalized and withdrawn from the well bore by a single wireline run.

The means for slidably entering and locking the plug assembly may comprise a plurality of collet fingers for engaging a top surface of the plug assembly and remaining stationary upon further movement of a remainder of the adaptor apparatus within the plug assembly.

A coil spring is compressed by the further movement until a finger mandrel disengages the collet fingers to an extent permitting the coil spring to push the collet fingers back to a starting position.

The means for sealing and means for unsealing the plug assembly includes a seal for selectively engaging and disengaging a port of the plug assembly.

The further means responsive to pulling the adaptor apparatus for latching the plug assembly to the adaptor apparatus includes a shear pin.

The adaptor apparatus has further means responsive to the pulling of the adaptor apparatus for latching the plug assembly to the adaptor apparatus including a finger mandrel that moves a finger collet into latching engagement with the plug assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of an adaptor apparatus in accordance with the invention;

FIGS. 2-6 are likewise cross-sectional views of the adaptor apparatus in engagement with the plug assembly in various positions incident to the retrieval operation.

DESCRIPTION OF THE EMBODIMENTS

With reference to FIG. 1, there is shown an embodiment of the adaptor apparatus designated generally as A. The apparatus includes a fish neck top sub 1 integral with a sealing prong 2. Mounted thereon are cooperating finger collet 3 and finger mandrel 4. A coil spring 5, shear ring 6 and spring housing 7 are mounted on the sealing prong 2. On an opposite end of the sealing prong, there is provided a pair of packing seals 9 adjacent bottom sub 10 of the ceiling prong 2. On an opposite end of the sealing prong 2, shear pin sleeve 8 and shear pin 11 are mounted. An emergency release shear pin 12 is positioned adjacent coil spring 5 and under spring housing 7.

With reference to FIG. 2, there is shown a plug assembly designated generally as B. This assembly is shown in association with the adaptor apparatus as shown and described with respect to FIG. 1.

With further reference to FIG. 2, the adaptor apparatus is run in hole on a pulling tool (not shown) that engages the fish neck 1 of the adaptor. When entering the plug assembly fish neck 15, the collet fingers 3 will engage the plug assembly fish neck. Pushing downward will move the entire adaptor assembly downwardly except for the collet fingers 3 which will remain stationary and will compress the coil spring 5 until the finger mandrel 4 no longer supports the collet fingers sufficiently to let the fingers collapse through the plug assembly fish neck 15. The adaptor apparatus will stop moving downward when the spring housing 7 abuts the top of the plug assembly fish neck 15. At this position, the seals 9 do not straddle ports 13 in the plug assembly and thus the assembly will not hold pressure from above and below. This is the position shown in FIG. 2. Downward movement of the adaptor apparatus will shear the shear pin 11 and allow the fish neck 1, the sealing prong 2, and the seals 9 to move downward until the sealing prong abuts the internal shoulder 18 in the plug assembly housing. In this position, the seals 9 will now straddle the ports 13 and the plug assembly will hold pressure from above and below. This is the position shown in FIG. 3. Further downward movement will release the pulling tool which can be removed and retrieved at the surface, leaving the adaptor apparatus and plug assembly downhole.

Pressure must be equalized across the plug assembly before retrieval of the assembly. Otherwise, there is a possibility of pressure blowing the tools uphole when no longer locked in place. The plug assembly can be retrieved with one run of a pulling tool (not shown). The pulling tool will latch onto the fish neck 1 of the adaptor, and the adaptor will latch into the internal fish neck 15 of the plug assembly. Pulling upward will move the sealing prong 2 upward until it abuts finger mandrel 4. The seals 9 will no longer be straddling the ports 13 of the plug housing and the pressure will equalize across the assembly. The adaptor apparatus and plug assembly are now ready for retrieval. This is the position shown in FIG. 4.

Because the pressure is equalized across the plug assembly, pulling upward will release the plug assembly. The finger collet 3 is fully supported and will pull against the inner shoulder 14 of the plug assembly. By upward movement, the finger collet 3 pulls the inner shoulder 14 upwardly. The plug fish neck 15 and expander mandrel 16 will move upward causing the plug assembly dogs 17 to be unsupported. The adaptor apparatus and plug assembly can be removed and retrieved at the surface. This is the position shown in FIG. 5.

Should there be any difficulty in retrieving the assembly, there is an emergency shear release provided. When pulling upward, the finger collet 3 located against the inner shoulder 14 of the plug assembly also abuts shear ring 6. If the assembly can not be retrieved, then heavy jarring movement upward will shear emergency release pin 12. The collet 5 and the shear ring 5 will then travel downward relative to the sealing prong 2 and finger mandrel 4. Then the collet 3 will no longer be supported and can collapse through the lock fish neck 1 inside diameter. The adaptor can then be removed and retrieved at the surface. This is the view shown in FIG. 6. 

1. An adaptor apparatus for use in facilitating removal and retrieval of a plug assembly from a well bore, said apparatus comprising: means for slidably entering and locking said plug assembly within said well bore in internal, abutting engagement within said plug assembly at a first location; means for unsealing said plug assembly when said adaptor apparatus is further slidably moved within said plug assembly to a second location; means for connecting an end of said adaptor apparatus to pulling means for pulling said adaptor apparatus from said well bore; means responsive to said pulling of said adaptor apparatus for unsealing said plug assembly; further means responsive to said pulling of said adaptor apparatus for latching said plug assembly to said adaptor apparatus; whereby said plug assembly and said adaptor unitarily equalized and apparatus may be unitarily equalized and withdrawn from said well bore by a single wireline run.
 2. The adaptor apparatus of claim 1, wherein said means for slidably entering and locking said plug assembly comprises a plurality of collet fingers for engaging a top surface of said plug assembly and remaining stationary upon further movement of a remainder of said adaptor apparatus within said plug assembly.
 3. The adaptor apparatus of claim 2, wherein a coil spring is compressed by said further movement until a finger mandrel disengages said collet fingers to an extent permitting said coil spring to push said collet fingers back to a starting position.
 4. The adaptor apparatus of claim 3, wherein said means for sealing and said means for unsealing said plug assembly includes a seal for selectively engaging and disengaging a port of said plug assembly.
 5. The adaptor apparatus of claim 4, wherein said further means responsive to said pulling of said adaptor apparatus for latching said plug assembly to said adaptor apparatus for latching said plug assembly to said adaptor apparatus includes a shear pin.
 6. The adaptor apparatus of claim 4, wherein said further means responsive to said pulling of said adaptor apparatus for latching said plug assembly to said adaptor apparatus includes a finger mandrel that moves a finger collet into latching engagement with said plug assembly. 